| Sinnai to Marco de Canavezes | 922.80 mi (1,485.10 km) |
| Sinnai to Marinha Grande | 965.40 mi (1,553.67 km) |
| Sinnai to Massama | 990.76 mi (1,594.47 km) |
| Sinnai to Matosinhos | 951.38 mi (1,531.09 km) |
| Sinnai to Mealhada | 937.90 mi (1,509.41 km) |
| Sinnai to Melgaco | 933.63 mi (1,502.53 km) |
| Sinnai to Melres | 935.51 mi (1,505.56 km) |
| Sinnai to Mira | 952.74 mi (1,533.28 km) |
| Sinnai to Miranda do Corvo | 932.34 mi (1,500.45 km) |
| Sinnai to Mirandela | 873.91 mi (1,406.42 km) |
| Sinnai to Mogadouro | 849.08 mi (1,366.45 km) |
| Sinnai to Moimenta da Beira | 894.35 mi (1,439.32 km) |
| Sinnai to Moita | 976.25 mi (1,571.12 km) |
| Sinnai to Moncao | 944.19 mi (1,519.53 km) |
| Sinnai to Montalegre | 907.30 mi (1,460.16 km) |
